Technology Ideas to Change the World

So, I recently downloaded Lisp on my Mac and am reading some of Paul Graham's material. He mentioned in it that software still has decades left to run and there will some be many ideas and startups that will come from this field which would change the world. Can anyone think of any examples? I have to admit I am a bit of a skeptic, Google, Yahoo, FaceBook, Microsoft, Apple, Tesla, Baidu ... big technology companies dominate the world now and they all seem to be mainly copycats of each other. Is there space for disruptive startups and what would these be like? If i were a idealistic young thing wanting to change the world with software, what would you suggest I create ? CaiGengYang